基于Illumina MiSeq 高通量测序技术分析广西无盐发酵酸笋中细菌多样性

以10年老酸水泡制酸笋样品（BSFAF）、发酵6个月块状酸笋（MBSF）和丝状酸笋样品（FBSF）为研究对象,应用Illumina MiSeq高通量测序技术并通过生物信息统计与分析,探索广西无盐发酵酸笋样品中细菌菌群结构及多样性。结果表明：3组酸笋样品共得到148 656个有效的序列数（Tags）,聚类后总共得到1 116个分类操作单元(OTUs）。根据物种注释结果,在3组酸笋样品中共注释到12个门、23个纲、37个目、98个科和190个属。在门分类水平上,3组样品中厚壁菌门（Firmicutes）占绝对优势,其次是变形杆菌门（Proteobacteria）和放线菌门（Actinobacteria）;在属分类水平上,乳杆菌属（Lactobacillus）、乳球菌属（Lactococcus）和魏斯氏菌属（Weissella）是3组样品中的优势菌属。其中,丝状酸笋（FBSF）组的香农（Shannon）、辛普森（Simpson）及ACE指数均显著高于其他两组,且乳杆菌属（Lactobacillus）、乳球菌属（Lactococcus）和魏斯氏菌属（Weissella）的平均相对丰度总和最高,可达99.8%。因此,以泉水泡制发酵丝状竹笋生产酸笋可能更佳。     

竹笋热烫处理过程中颜色变化的动力学模型

为研究竹笋在热烫处理过程中的颜色变化规律,对竹笋样品分别进行不同温度（80、85、90、95、100 ℃）、不同时间（3、6、9、12、15、18、21 min）的热烫处理,得到其亮度（L*）值、红绿（a*）值、黄蓝（b*）值的变化规律,并以此为依据计算竹笋总色差（ΔE）、饱和度、褐变指数（BI）等指标。对这些颜色指标变化分别应用零级、一级反应动力学模型进行拟合分析,结果表明：竹笋的L*、a*的反应速率常数（k）随着热烫温度升高而增加趋势,而b*、ΔE、饱和度和BI的k值均随热烫温度升高而呈减小的趋势。拟合回归系数R2表明零级反应动力学模型更好地描述了竹笋热烫处理过程中颜色的动态变化。     

Evaluating the use of plant hormones and biostimulators in forage pastures to enhance shoot dry biomass production by perennial ryegrass (Lolium perenne L.)

Fertilisation of established perennial ryegrass forage pastures with nitrogen (N)‐based fertilisers is currently the most common practice used on farms to increase pasture forage biomass yield. However, over‐fertilisation can lead to undesired environmental impacts, including nitrate leaching into waterways and increased gaseous emissions of ammonia and nitrous oxide to the atmosphere. Additionally, there is growing interest from pastoral farmers to adopt methods for increasing pasture dry matter yield which use ‘natural’, environmentally safe plant growth stimulators, together with N‐based fertilisers. Such plant growth stimulators include plant hormones and plant growth promotive microorganisms such as bacteria and fungi (‘biostimulators’, which may produce plant growth‐inducing hormones), as well as extracts of seaweed (marine algae). This review presents examples and discusses current uses of plant hormones and biostimulators, applied alone or together with N‐based fertilisers, to enhance shoot dry matter yield of forage pasture species, with an emphasis on perennial ryegrass. © 2015 Society of Chemical Industry     

Behavioral and electrophysiological responses of natural enemies to synomones from tea shoots and kairomones from tea aphids,Toxoptera aurantii

Olfactometer bioassays and electrophysiological studies showed that the lacewing, Chrysopa sinica, the aphid parasitoid, Aphidius sp., and the coccinellid, Coccinella septempunctata, all responded to volatiles from tea aphids, Toxoptera aurantii, to hexane or ether rinses of tea aphid cuticles, and to synomones released by aphid-damaged tea shoots, as well as to the tea shoot–aphid complex. Each natural enemy spent more time searching on a filter paper treated with tea aphid honeydew than on a blank control filter paper. The interaction between synomones from aphid-damaged shoots and kairomones from tea aphids enhanced the responses to the plant–host complex. There was a significant, logistic dose–response relationship between the number of natural enemies responding and the odor stimulus concentration. Volatile components from the plant–host complex, obtained by air entrainment, were identified by their mass spectra and retention times and confirmed by comparison with standard samples. These were (Z)-3-hexen-1-ol, benzaldehyde, (E)-2-hexenal, (Z)-3-hexenyl acetate, ocimene, linalool, geraniol, indole, and (E)-2-hexenoic acid. The main components in a hexane rinse from tea aphid cuticle were benzaldehyde, undecane, 2,5-hexanedione, 2,5-dihydrothiophene, linalool, 4-methyl-octane, and eicosane, whereas the main components from an ether rinse were (E)-2-hexenoic acid, heptadecane, pentadecane, eicosane, tetratetracontane, and nonadecane. Benzaldehyde elicited the strongest responses from natural enemies in the olfactometer and the largest electroantennogram (EAG) responses. While the amount of odor was small, Coccinella septempunctata was slightly more sensitive than Chrysopa sinica and Aphidius sp. An increase in doses of benzaldehyde, (E)-2-hexenal, and (Z)-3-hexenyl acetate caused the EAG responses of each natural enemy to decrease. When the doses of (Z)-3-hexen-1-ol, linalool, and geranoil increased, EAGs of Chrysopa sinica and Aphidius sp. increased, but EAGs of Coccinella septempunctata decreased. When the dose of indole increased, EAGs of Coccinella septempunctata decreased, but those of Aphidius sp. increased. This study demonstrates that tea shoot–aphid complexes emit volatile synomones, while the odors from tea aphids, aphid cuticle extracts, and tea aphid honeydew contain kairomones, to which the natural enemies show a logistic dose–response.     

反舰导弹武器系统的火力分配方法研究

分别以单目标舰船和舰船编队为打击对象,引入要求毁伤概率和射击效益作为相应的射击指标,提出了反舰导弹武器系统的火力分配方法.计算结果表明以上方法是行之有效的.     

Structural characteristics,physicochemical properties and prebiotic potential of modified dietary fibre from the basal part of bamboo shoot

The basal part of bamboo shoot is a novel resource to produce dietary fibre (BDF). However, its insolubility in water, stiff texture and low degradability limit its applicability in foods. This study explored the feasibility of improving the structural and functional properties of BDF by enzymatic hydrolysis and dynamic high-pressure micro-fluidisation (DHPM). Both methods are efficient to reduce the fibre particle size and caused significantly increased roughness on the fibre surface, especially for the porous structure after DHPM treatment. Crystallinity of DHPM-modified fibres was increased from 23.01% to 33.53%, due to the disruption of lignin and hemicellulose, which was further confirmed by the FT-IR spectra. The modified fibres exhibited significantly enhanced swelling capacity and holding water/oil capacities. Moreover, the modified fibres exhibited improved in vitro prebiotic property, which could constantly supply the carbon source and stimulate the growth of Lactobacillus acidophilus ATCC 4356 and Bifidobacterium longum ATCC 15707.     

壳聚糖涂膜保鲜竹笋研究

选用壳聚糖作为涂膜剂处理带壳小竹笋，在4℃低温，相对湿度94%条件下贮藏保鲜25d。贮藏期间对竹笋的失重率、纤维素和VC含量以及氨基酸总量进行了测定。试验结果表明：1.5%壳聚糖混入1.0%对羟基苯甲酸乙酯制成的涂膜剂有较好的保鲜效果，抑制失重和纤维素含量增加有明显效果。用同法处理的带壳乌笋保鲜效果比雷笋好。     

超微粉碎对竹笋壳粉理化性质的影响

本文研究了超微粉碎技术对竹笋壳粉的基本组成、物理性质以及对亚硝酸根和胆固醇的吸附能力的影响。结果显示:超微粉碎处理后竹笋壳粉的水分、灰分、蛋白质和膳食纤维含量保持稳定的同时其平均粒径由383.90 μm降至12.69 μm。另外粉体亮度显著提升(p<0.05),红色度和黄色度均显著降低(p<0.05)。竹笋壳超微粉的持水性和持油性无显著变化,溶胀性显著降低(由7.48 mL/g降至5.50 mL/g)(p<0.05)。竹笋壳超微粉对亚硝酸根离子和胆固醇吸附量分别为558.26 μg/g(pH2.0)、346.19 μg/g(pH7.0),吸附能力分别提升了24.6%和9.1%(p<0.05)。傅立叶红外光谱显示超微粉碎对竹笋壳粉中羟基,糖类亚甲基以及木质素中芳香族化合物没有影响。同时扫描电镜观察发现超微粉碎造成粉体颗粒表面呈蜂窝状。故超微粉碎处理能够较好的维持竹笋壳粉的基本组成成分,并改善其理化性质。     

不同预处理方法减少食品中二氧化硫残留量比较的研究

采用碘吸收滴定法测定了几种食品中二氧化硫的残留量及比较了不同预处理方法对二氧化硫含量的影响。以白木耳,笋衣为原料,采用GB/T 5009.34的改进方法测定食品中二氧化硫残留量,比较了25℃自来水浸泡、煮沸法、小苏打浸泡法,60℃热水浸泡法及醋酸浸泡法对样品中二氧化硫含量的影响。五种方法中除醋酸浸泡法减少样品中二氧化硫的效果最差,其余4种方法均能有效地降低食品中二氧化硫的残留量,其中沸水煮沸20min后能完全驱除二氧化硫,该方法简便、实用且易于操作;其次是60℃水浴3h,然后是0.5%小苏打溶液浸泡5 6h和25℃自来水浸泡处理5 6h。     

Excessive nitrogen supply and shoot trimming can impair colour development in Pinot Noir grapes and wine

We investigated the effects of nitrogen supply and shoot trimming on mature, field-grown Pinot Noir ( Vitis vinifera L.) vines. Ammonium nitrate (0, 30, 60, 90 kg N/ha) was applied at the beginning of flowering. Shoots were topped either once (at fruit set), or twice, (at fruit set and during the lag-phase of berry growth). Neither treatment affected grape berry and skin weights, yield and grape sugar, but high rates of nitrogen increased malic acid and reduced skin phenols, flavonols and anthocyanins. Malvidin-3-glucoside was the most abundant anthocyanin in skins and wine. It accounted for 75% of the total anthocyanins at the beginning of fermentation and its relative proportion increased to 95% in the finished wine.
Increases in anthocyanin concentration at the beginning of fermentation and before malolactic fermentation, were followed by declines during the later stages of alcoholic and malolactic fermentation. High nitrogen supply decreased anthocyanins in the juice and wine, increased pH and increased the percentage of malvidin-3-glucoside. Repeated shoot topping gave lower wine total phenols and anthocyanins and thus enhanced the nitrogen effect. Wine susceptibility to oxidation increased with higher pH and lower anthocyanin content. The best treatment combination for fruit and wine quality, in terms of colour and oxidative stability, was low nitrogen/single topping and the worst combination was high nitrogen/repeated topping. These results suggest that a combination of high rates of nitrogen fertiliser and repeated shoot trimming can decrease potential fruit and wine quality.